The invention relates to an actuator and a vehicle protection system comprising an actuator, especially an airbag system.
For the protection of vehicle occupants or persons outside the vehicle time is a critical factor. Triggering the protection systems such as e.g. airbags, belt tensioners or a steering column dampening has to take place already milliseconds after a crash so that these systems car develop a sufficient protective effect.
Airbags, especially in vehicle safety systems, which are intended to dampen the impact of a person in the case of crash upon activation thereof are filled by a compressed gas source and are inflated from a folded state. In order to achieve this change of shape within short time and in order to take also great forces acting during crash into account, the airbag is tightly inflated so that high internal pressure is prevailing in its interior. In this way the absorbing effect of the airbag is also given in the case of a tall and heavy person. For a light, petite person or an unfavorable seating position with respect to the airbag, however, too high internal pressure of the airbag may inhibit the restraining effect. For this reason, airbags are frequently provided with exhaust orifices through which gas can escape to reduce the internal pressure.
It is also known to first separate a partial volume of the airbag and fill the same only on demand, for example by destroying a separating tear seam.
In order to adjust the optimum internal pressure of the airbag as needed depending on the situation, various mechanisms are used by which exhaust orifices, for example, can be released or closed. Solutions for transmitting the trigger pulse from the control to the respective mechanism at the protection system are usually complicated and expensive, however.